1. Technical Field
The present invention relates to a water treatment device and, more particularly, to a gravity-flow water purifier whose filtering action need not be driven by electricity and whose filter elements can be conveniently installed, removed, and cleaned.
2. Description of Related Art
In a conventional water filter device, the filter unit is typically placed in a closed housing and submerged in the water to be filtered. Moreover, the water filter device must be connected to an external power source, so a boost pump is electrically driven to raise the water pressure at the water inlet end of the filter unit. The high water pressure urges clean water molecules to pass through a membrane, which nevertheless prevents impurities and harmful substances from passage. Thus, solid-liquid separation is achieved to generate purified water.
While using an external power source to pump water through the filter unit accelerates the filtering process, an electric water filter device gives rise to power consumption concerns and must be used where electricity is available. This presents practical difficulties in less developed areas or areas with low water supply pressure.
As a solution to the aforesaid problem, it has been proven effective to move the feed water tank to a relatively high position, so that the potential energy of feed water and consequently the water pressure at the water inlet end of the filter unit are increased to enable automatic filtering. However, the foregoing arrangement requires additional pipelines and release valves, which is costly and structurally undesirable.
In addition, the filter elements, or filter materials, in a common water filter device are expendable and are usually disposed inside the housing of the water filter device. Therefore, when the filter elements are soiled or blocked and need replacing or cleaning, it is necessary to open the housing and adequately discharge the water therein before the filter unit can be taken out for replacement. The complicated disassembly process not only is time-consuming and laborious, but also can be problematic if the water filter device is a massive machine. This is also an important issue that the filter device industry has been seeking to address.